Combined gage wheel and integrated transport system

ABSTRACT

A steering system for an agricultural machine includes a first and second wheel assembly. Each wheel assembly includes an axle assembly including an axle, wheels rotatably connected to the axle, and a double-action hydraulic cylinder. In some embodiments, the double-action hydraulic cylinder is configured to pivot the wheels in either direction to indicate a direction of turn. In some embodiments, the double-action hydraulic cylinder of the first wheel assembly is hydraulically linked in its operation to an operation of the double-action hydraulic cylinder of the second wheel assembly.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/240,225, filed Jan. 4, 2019, which claims the benefit of U.S.Provisional Patent Application No. 62/764,936, filed Aug. 15, 2018, bothof which are incorporated herein by reference in their entirety.

FIELD OF THE DISCLOSURE

The present specification relates generally to the field of agriculturalequipment transportation. More particularly, the present specificationrelates to a transportation and steering system for agriculturalequipment.

BACKGROUND

A harvesting machine generally includes a header and a vehicle (e.g., atractor) for carrying the header. One end of the header is attached tothe vehicle. The other end of the header includes ground wheels forsupporting the vehicle in movement across the ground. When the headerneeds to be transported to another location after the harvestingoperation, the header may be detached from the vehicle and a trailer isusually used for transporting the header. Other agricultural equipmentmay also need to be transported from one field to another.

SUMMARY

One implementation of the present disclosure is a steering system for anagricultural machine. The steering system includes a first and secondwheel assembly. Each wheel assembly includes an axle assembly includingan axle, wheels rotatably connected to the axle, and a double-actionhydraulic cylinder. In some embodiments, the double-action hydrauliccylinder is configured to pivot the wheels in either direction toindicate a direction of turn. In some embodiments, the double-actionhydraulic cylinder of the first wheel assembly is hydraulically linkedin its operation to an operation of the double-action hydraulic cylinderof the second wheel assembly.

In some embodiments, the wheels of each wheel assembly are spaced adistance apart substantially equal to or greater than the width of theagricultural machine.

In some embodiments, the axle assembly includes a tongue connected tothe double-action hydraulic cylinder. The tongue is configured to pivotabout a pivot point, and is configured to steer the wheels through tierods connected to the tongue and the wheels, according to someembodiments.

In some embodiments, the double-action hydraulic cylinder is attached onone end to the tongue, and on the other end to the axle.

In some embodiments, the tongue is configured to either be pivoted by anexpansion or retraction of the double-action hydraulic cylinder, or tobe pivoted by an external force and drive the expansion or retraction ofthe double-action hydraulic cylinder.

In some embodiments, the double-action hydraulic cylinder of the firstwheel assembly is configured to be expanded or retracted by the pivotingof the tongue of the first wheel assembly and is hydraulically linked tothe double-action hydraulic cylinder of the second wheel assembly. Insome embodiments, the double-action hydraulic cylinder of the secondwheel assembly is configured to drive the tongue of the second wheelassembly to control the turn of the wheels of the second wheel assembly.

In some embodiments, the tongue of the first wheel assembly isconfigured to selectively attach to a vehicle for transportation or toselectively attach to a beam configured to attach to the vehicle fortransportation. In some embodiments, the tongue is further configured tobe pivoted by a motion of the vehicle.

In some embodiments, the double-action cylinder of the first wheelassembly is configured to hydraulically link to the double-actioncylinder of the second wheel assembly by transferring hydraulic fluidfrom the double-action cylinder of the first wheel assembly to thedouble-action cylinder of the second wheel assembly to expand or retractthe double-action cylinder of the second wheel assembly.

In some embodiments, the wheel assemblies include a spring. The springis configured to attach at one end to the tongue and at the other end toa protrusion from the axle, and apply a force to an outside wheel of thewheels according to some embodiments. The force is transmitted throughthe tongue and the tie rods to the outside wheel according to someembodiments. In some embodiments, the outside wheel is the wheel at anoutermost distance from a center of a turn.

In some embodiments, the spring connects at one end to a tongue half Insome embodiments, the tongue half is pinned to the tongue.

Another implementation of the present disclosure is a wheel assembly foran agricultural machine. The wheel assembly includes a set of wheels, aheader, a double-action cylinder, and a tongue. The header is configuredto rotate between a field mode and a transportation mode according tosome embodiments. In some embodiments, the double-action cylinder isconfigured to expand or retract. In some embodiments, the expanding andretracting of the double-action cylinder steers a set of wheels. In someembodiments, the tongue is configured to connect to the double-actioncylinder and pivot based on the expansion or retraction of thedouble-action cylinder.

In some embodiments, the wheel assembly includes an axle. In someembodiments, the double-action cylinder connects at one end to the axle,and at the other end to the tongue.

In some embodiments, the wheel assembly includes a set of tie rods,wherein the tie rods each connect at one end to the tongue and areconfigured to steer the wheels based on the pivoting of the tongue.

In some embodiments, the tongue is configured to either pivot about apivot point, drive the expansion and retraction of the double-actioncylinder and drive the tie rods to steer the wheels, or to be driven bythe expansion and retraction of the double-action cylinder, pivot aboutthe pivot point, and drive the tie rods to steer the wheels based on theexpansion and retraction of the double-action cylinder.

In some embodiments, the wheel assembly includes a spring. In someembodiments, the spring is configured to attach at one end to the tongueand at the other end to a protrusion from the axle. In some embodiments,the spring may apply a force to an outside wheel of the wheels. In someembodiments, the force is transmitted through the tongue and the tierods to the outside wheel. In some embodiments, the outside wheel is thewheel at an outermost distance from a center of a turn.

In some embodiments, the spring connects at one end to a tongue half Insome embodiments, the tongue half is pinned to the tongue.

In some embodiments, the double-action cylinder is configured tohydraulically link to a second double-action cylinder. In someembodiments, the double-action cylinder transfers hydraulic fluid to thesecond double-action cylinder to expand or retract the seconddouble-action cylinder.

In some embodiments, the wheels are spaced a distance apart greater thanor equal to the width of the agricultural machine.

Another implementation of the present disclosure is a method forfour-wheel steering on an agricultural machine. The method includesreceiving a force input to a tongue. The force input to the tongueindicates a direction and magnitude of a turn of a vehicle and thetongue is configured to pivot in a direction and amount proportional tothe direction and magnitude of the turn of the vehicle. The methodfurther includes expanding or retracting a first double-action cylinderbased on the direction and amount of pivot of the tongue, expanding orretracting a second double-action cylinder based on the expansion andretraction of the first double-action cylinder, steering a first set ofwheels based on the direction and amount of the pivot of the tongue, andsteering a second set of wheels based on the expansion and retraction ofthe second double-action cylinder. In some embodiments, the firstdouble-action cylinder is connected at an end of the tongue.

In some embodiments, the method includes receiving a force input to thetongue through a beam connected to the vehicle.

In some embodiments, the method includes expanding or retracting thesecond double-action cylinder based on the expansion and retraction ofthe first double-action cylinder by transferring hydraulic fluid out ofa first chamber of the first double-action cylinder into a secondchamber of the second double-action cylinder and transferring hydraulicfluid out of a second chamber of the first double-action cylinder into afirst chamber of the second double-action cylinder.

In some embodiments, the method includes steering the first set ofwheels based on the direction and amount of the pivot of the tongue bydriving a set of tie rods with the tongue. In some embodiments, the setof tie rods are connected to the tongue and the first set of wheels.

In some embodiments, the method includes steering the second set ofwheels by pivoting a second tongue connected to and pivoted by thesecond double-action cylinder, and driving a second set of tie rodsconnected to the second tongue and the second set of wheels.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments will become more fully understood from thefollowing detailed description, taken in conjunction with theaccompanying drawings, wherein like reference numerals refer to likeelements, and:

FIG. 1 is a perspective view schematic drawing of an agriculturalharvester, including an agricultural harvesting head assembly, accordingto some embodiments.

FIGS. 2A-B are each a perspective view schematic drawing of theagricultural harvesting head assembly of FIG. 1 including an axle andwheel assembly, depicting a field mode and a transportation mode,according to some embodiments.

FIG. 3 is a bottom perspective view schematic drawing of the axleassembly of FIG. 1, according to some embodiments.

FIG. 4 is a top perspective view schematic drawing of the axle assemblyof FIG. 1, according to some embodiments.

DETAILED DESCRIPTION

The detailed description set forth below is intended as a description ofvarious configurations of the subject technology and is not intended torepresent the only configurations in which the subject technology may bepracticed. The appended drawings are incorporated herein and constitutea part of the detailed description. The detailed description includesspecific details for the purpose of providing a thorough understandingof the subject technology. However, it will be clear and apparent tothose skilled in the art that the subject technology is not limited tothe specific details set forth herein and may be practiced using one ormore implementations.

Referring generally to the FIGURES, the present disclosure provides asteering and transportation system for transporting agriculturalharvesting equipment. In some embodiments, the agricultural harvestingequipment is an agricultural harvesting head detached from a combine. Insome embodiments, other agricultural equipment may use the steering andtransportation system for transportation. In some embodiments, thecombine and the agricultural harvesting head are used to harvest crops,process the crops and transport them to storage areas. During harvestingoperation, the combine pushes the agricultural harvesting head whichtravels along the ground, supported on one end by the combine, andsupported on the ground by wheels (also referred to as gage wheels),according to some embodiments. In some embodiments, the agriculturalharvesting head may sever the crop and transfer it into the combine forprocessing and storage. In some embodiments, the harvesting headincludes a pair of similar wheel assemblies near both ends of theharvesting head. When the harvesting head must be transported (e.g., onroads from one field to another), the wheel assemblies rotate 90 degreesand lock in position, according to some embodiments. The harvesting headmay then be attached to a vehicle for transportation. In someembodiments, each of the wheel assemblies includes a double-actinghydraulic cylinder configured to turn the wheels by moving tie rods eachconnected to the hub assembly of the wheel they are configured to steer.In some embodiments, the double-acting hydraulic cylinder of each wheelassembly are hydraulically connected to each other, such that both pairsof wheels can operate to aid turning, providing a four-wheel steeringsystem. The four wheel steering system may aid in sharp turns bothduring the harvesting operation as well as during transportation of theagricultural harvesting head. Additionally, in some embodiments thedistance between the wheels is the same for both wheel assemblies. Thismay provide better support during sharp turns, and prevents rollover ortipping from occurring in some embodiments.

Sometimes when the user operating the combine makes a sharp turn (toturn around after completing one pass through the crop field, or toavoid objects or trees), the harvesting head wheels skid (i.e., thefrictional interface between the point of the wheel contacting theground becomes a dynamic frictional interface rather than a staticfrictional interface which is present when the wheel rolls). This maydamage the wheels or any part of the axle assembly by introducingtransverse thrust loads or other loads into the axle assembly and thewheels. In some cases, skidding may cause an undesirable load to beintroduced into the agricultural harvesting head. Skidding may alsocause ruts in the soil and dirt clumping. Therefore, a harvesting headwhich has wheels configured so that they do not skid when undergoingsharp turns is advantageous since it reduces the above mentionedproblems associated with skidding wheels. In some embodiments, a forceis applied to an outside wheel by a centering bar. This force implementsa rollover feature which prevents the wheels from skidding and reducesthe problems associated with skidding wheels described hereinabove.Additionally, this force causes the wheels to return back to a forwarddirection of travel after a turn.

Referring now to FIG. 1, an agricultural harvesting machine 100 is shownaccording to some embodiments. The agricultural harvesting machine 100includes a combine 102 and a harvesting head assembly 200 according tosome embodiments. The harvesting head assembly 200 is supported on oneend by the combine 102, and supported above the ground by wheels 224(see FIGS. 2-4) according to some embodiments. As the agriculturalharvesting machine 100 moves in harvesting direction of travel 104, theharvesting head assembly 200 severs the crop, and transports it tocombine 102 for processing and storage according to some embodiments. Insome embodiments, harvesting head assembly 200 is detachably connectedto combine 102. It should be noted that the present disclosurereferences a harvesting head assembly 200 to be transported, however,any other agricultural machine that requires transportation may use thesteering/transportation-system described, and while thesteering/transportation system may be used to transport harvesting headassembly 200 the use of harvesting head assembly 200 is only onepossible application of the steering/transportation system.

Referring now to FIGS. 2A-B, the agricultural harvesting head assembly200 is shown, detached from combine 102. The agricultural harvestinghead assembly 200 is shown to include wheel assembly 208 according tosome embodiments. FIGS. 2A-B show only one wheel assembly 208, howeverthe wheel assembly 208 on the opposite end of agricultural harvestinghead assembly 200 may be symmetrical, so that whatever is said of thewheel assembly 208 shown in FIGS. 2A-B may also be said of the wheelassembly 208 connected at the opposite end of the harvesting headassembly 200, according to some embodiments. FIGS. 2A-B also showcoordinate system 108 for illustrative and explanatory purposes, havingthree axes (104, 106, and 108) which may indicate direction of motion ordirection in space. The three axes 104, 106, and 108 are orthogonal toeach other.

FIG. 2A shows wheel assembly 208 connected to the agriculturalharvesting head assembly 200 in a harvesting mode of operation accordingto some embodiments. Wheel assembly 208 is shown to include wheels 224and axle assembly 204 according to some embodiments. Wheels 224rotatably connect to the axle assembly 204 and the axle assembly 204connects to the agricultural harvesting head assembly 200 according tosome embodiments. In the harvesting mode of operation (shown in FIG.2A), a centerline 220 which extends through the centers of wheels 224 isgenerally perpendicular to the harvesting direction of travel 104 andgenerally parallel to a longitudinal direction 106 of harvesting headassembly 200, according to some embodiments. Wheels 224 are thereforeconfigured to support the harvesting head assembly 200 and roll in theharvesting direction of travel 104 according to some embodiments. Whenthe harvesting head assembly 200 must be transported, wheel assemblies208 are configured to rotate 90 degrees as shown in FIG. 2B so that theygenerally point in longitudinal direction 106 according to someembodiments. In some embodiments, wheel assemblies 208 rotate 90 degreesabout centerline 212. Centerline 212 may extend generally through thecenter of axle assembly 204 and may be generally parallel to axis 108according to some embodiments. In some embodiments, centerline 212 ishalf way in between the wheels 224. When the wheel assemblies 208 haveboth rotated 90 degrees, the harvesting head assembly 200 may betransported in direction 106 (if the wheel assembly 208 shown is thefront wheel assembly 208), or in the opposite direction (if the wheelassembly 208 shown is the rear wheel assembly 208), according to someembodiments. Harvesting head assembly 200 as shown in FIG. 2B may beattached to a vehicle and may be transported on roads according to someembodiments. In some embodiments, harvesting head assembly 200 may beloaded into a trailer. In some embodiments, when harvesting headassembly 200 is loaded into the trailer, the wheel assemblies 208 arecompletely removed. In some embodiments, the wheel assemblies 208 areretracted for trailer transportation such that the wheel assemblies 208do not interfere with the trailer during transportation.

FIGS. 2A-B also show the wheels 224 spaced a distance 216 apartaccording to some embodiments. Both front and rear wheel assemblies 208may have wheels 224 spaced distance 216 apart, according to someembodiments. In some embodiments, the wheel assemblies 208 may havewheels 224 spaced apart at different distances. For example, the wheelassembly 208 shown in FIGS. 2A-B may have wheels 224 spaced distance216, while the wheel assembly 208 at the opposite end of harvesting headassembly 200 may have wheels 224 spaced a distance greater than distance216 according to some embodiments. In some embodiments, wheel assembly208 at the opposite end of harvesting head 200 may have wheels 224spaced a distance less than distance 216. In some embodiments, the wheelassembly 208 with the wheels 224 spaced a greater distance apart thanthe opposite wheel assembly 208 may be the “front” of the harvestinghead assembly 200 during transportation. In some embodiments, the wheelassembly 208 with the wheels 224 spaced a lesser distance apart than theopposite wheel assembly 208 may be the “front” of the harvesting headassembly 200 during transportation. In some embodiments, the distancebetween wheels 224 is the same for both wheel assemblies 208 and eitherwheel assembly 208 may be the “front” or “rear” of the harvesting headassembly 200 during transportation. In some embodiments, the distancebetween wheels 224 is the same for both wheel assemblies 208 and one ofthe wheel assemblies 208 may be the “front” while the other wheelassembly 208 may be the “rear.”

Referring still to FIGS. 2A-2B, the wheels 224 are shown spaced distance216 apart. In some embodiments, distance 216 is substantially greaterthan the width of the harvesting head assembly 200 in direction 104. Insome embodiments, distance 216 is substantially equal to the width ofharvesting head assembly 200 in direction 104. This provides a stablesupport for the harvesting head assembly 200 during transportation,according to some embodiments. When the harvesting head assembly 200 istransported and goes around a sharp turn, inertial forces may cause theharvesting head assembly 200 to tip. For example, if the wheel assembly208 shown in FIGS. 2A-B is the “front” wheel assembly, and the usermakes a left turn, there may be a component of an inertial force fromthe center of gravity of the harvesting head assembly 200 in the 104direction. This force in the 104 direction may produce a moment aboutthe 106 axis. Advantageously, the wide wheel distance 216 provides acounter-moment according to some embodiments. In the case of a leftturn, the left wheel of the wheel assembly 208 (the right wheel from thevehicle operator's perspective) may provide a reactionary moment tocounter the tipping moment. The moment arm of the reactionary moment maybe up to half of the distance 216 (i.e., the distance from the center ofthe left wheel 224 to the center of the axle assembly 204 in the 104direction). The rear wheel assembly 208 may also provide acounter-moment to the tipping moment, according to some embodiments. Insome embodiments, both the front wheel assembly 208 and the rear wheelassembly 208 may provide a counter-moment to the tipping moment. Thedistance 216 provides a longer moment arm to counter the tipping momentwhich may occur during sharp turns or if the vehicle operator makes aturn at a high speed, since making a turn at a high speed produces alarge inertial force which may cause a tipping moment. Both the frontand the rear wheel assemblies 208 may have equal distances 216 anddistance 216 may be substantially equal to or greater than the width ofthe agricultural machine in the 104 direction. Advantageously, thisreduces the tendency of the agricultural machine (e.g., harvesting headassembly 200 as shown in FIGS. 1-2B) to tip during turns. Tipping maycause uneven distribution or excessive magnitude of loads to the axleassemblies 204 and the wheel assemblies 208 which may damage componentsin the axle assembly 204 or wheel assemblies 208 which may not bedesigned to undergo these excessive loads. Additionally, if theagricultural machine tips over completely (i.e., rollover), this maycause severe damage to the agricultural machine, which may be expensiveand time-consuming to repair. While the agricultural machine is beingrepaired, it cannot be used for agricultural purposes, and this cancause additional costs. Reducing the tendency of the agriculturalmachine to tip while making turns during transportation reduces thelikelihood of the agricultural machine rolling over, and enables thevehicle operator to make sharper turns without fear of tipping theagricultural machine. This also enables the vehicle operator greatermobility during transportation, and enables the vehicle operator to takeroutes which may require sharp turns. Embodiments in the presentdisclosure provide a solution to this problem by providing a wide wheelbase which reduces the likelihood and magnitude of tipping and mayreduce the likelihood of rollover occurring.

Referring now to FIGS. 3-4, the axle assembly 204 of the wheel assembly208 is shown in greater detail according to some embodiments. In FIGS.3-4, only one axle assembly 204 is shown, however it should beunderstood that everything said of the axle assembly 204 shown in FIGS.3-4 may be said of the axle assembly 204 at the opposing end ofharvesting head assembly 200 or more generally the agricultural machine.Axle assembly 204 is shown to include horizontal axle 226, header 256,tongue 244, double-action cylinder 230, struts 240, cylinder mount 236,tie rods 228, centering bar 252, and spring 248 according to someembodiments. Double-action cylinder 230 may be generally horizontallyoriented, and may be generally parallel to horizontal axle 226.

In some embodiments, double-action hydraulic cylinder 230 has outertubular member 232 (e.g., a barrel) which pivotally connects to cylindermount 236 and inner tubular member 234 (e.g., a rod) which pivotallyconnects to tongue 244. Cylinder mount 236 may be fixedly connected tohorizontal axle 226 or may be integrally formed with horizontal axle226, according to some embodiments. Tongue 244 is configured to pivotabout pin joint 254 according to some embodiments. Tongue 244 pivotallyconnects to tie rods 228 at joint 258 according to some embodiments.According to some embodiments, as double-action cylinder 230 expands orretracts, tongue 244 pivots about pin joint 254. For example, whendouble-action cylinder 230 expands, the end of tongue 244 whichpivotally connects to the inner tubular member 234 moves to the left,according to some embodiments. As the end of tongue 244 which pivotallyconnects to inner tubular member 234 moves to the left due to theexpansion of double-action cylinder 230, tongue 244 pivots about pinjoint 254, resulting in the end of tongue 244 which pivotally connectsto tie rods 228 moving to the right, according to some embodiments. Thepivoting of the tongue 244 may cause the tie rods 228 to move to theright, thus steering the wheels 224, according to some embodiments.Likewise, as the end of tongue 244 which pivotally connects to innertubular member 234 moves to the right due to the retraction ofdouble-action cylinder 230, tongue 244 pivots about pin joint 254,resulting in the end of tongue 244 which pivotally connects to tie rods228 moving to the left, according to some embodiments. In someembodiments, the tongue 244 is driven to pivot by the vehicle or anotherexternal force applied to the tongue, and the pivoting motion of thetongue 244 drives the expansion or retraction of double-action cylinder230 in the same configuration as discussed above.

Double-action cylinder 230 is shown to include inlet/outlet ports 260and 262 according to some embodiments. In some embodiments, inlet/outletports 260 and 262 are configured to allow the flow of hydraulic fluidinto or out of two chambers of double-action cylinder 230. In someembodiments, the flow of hydraulic fluid in and out of inlet/outletports 260 and 262 is driven by the pivoting motion of tongue 244 whichmay be driven by the vehicle. In some embodiments, the flow of hydraulicfluid in and out of inlet/outlet ports 260 and 262 causes thedouble-action cylinder 230 to expand or retract and drives the pivotingof the tongue 244. In some embodiments, inlet/outlet ports 260 and 262are configured to allow hydraulic fluid to flow between the front andrear double-action cylinders 230. In some embodiments, inlet/outletports 260 and 262 are configured to allow the hydraulic fluid to flowbetween either one or both the front and rear double-action cylinders230 and a hydraulic fluid reservoir or a pump. Inlet/outlet ports 260and 262 may each allow the inflow or outflow of hydraulic fluidaccording to some embodiments.

In some embodiments, the inlet/outlet ports 260 and 262 are configuredto interface with hydraulic lines to facilitate the flow of hydraulicfluid into and out of the double-action cylinder 230. For example, thefront double-action cylinder 230 may be configured to be driven into amore retracted state by the tongue 244, thus expelling hydraulic fluidfrom one chamber of the front double-action cylinder 230 according tosome embodiments. The hydraulic fluid expelled from one chamber of thefront double-action cylinder 230 may be directly introduced to a chamberof the rear double-action cylinder 230 causing the rear double-actioncylinder 230 to expand. In some embodiments, the front double-actioncylinder 230 may be driven into a more expanded state by the tongue 244,causing hydraulic fluid to be introduced into one chamber of the frontdouble-action cylinder 230. According to some embodiments, the hydraulicfluid introduced into one chamber of the front double-action cylinder230 may be drawn directly from the chamber of the rear double-actioncylinder 230, causing the rear double-action cylinder 230 to be driveninto a more retracted state. The flow of the hydraulic fluid between thefront and rear double-action cylinders 230 may be facilitated by theinlet/outlet ports 260 and 262 of the double-action cylinders 230, aswell as hydraulic lines connecting the inlet/outlet ports 260 and 262 ofthe front and rear double-action cylinders 230.

Double-action cylinders 230 may include a piston attached to innertubular member 234, configured to sealingly interface with an innerdiameter of outer tubular member 232 according to some embodiments. Insome embodiments, a seal may be used to sealingly interface an outerdiameter of the piston to the inner diameter of the outer tubular member232. The seal may be an O-ring made of rubber, or any other seal whichprevents the flow of fluid between the interface of the seal and theinner diameter of outer tubular member 232. Inner tubular member 234 andthe piston attached to it may longitudinally travel within the outertubular member 232 according to some embodiments. In some embodiments,the end of outer tubular member 232 which inner tubular member 234protrudes from is sealed, such that inner tubular member 234 can expandand retract (i.e., travel longitudinally within outer tubular member232), without hydraulic fluid leaking from the end which inner tubularmember 234 protrudes. In some embodiments, the seal interface betweenthe piston attached to the inner tubular member 234 and the outertubular member 232 divides the double-action cylinder 230 into twochambers.

The first chamber may be defined between the end of the outer tubularmember 232 which the inner tubular member 234 protrudes from, the innerwalls of the outer tubular member 232, and the sealed interface betweenthe piston attached to the inner tubular member 234 and the innerdiameter of the outer tubular member 232, according to some embodiments.The second chamber may be defined between an end of the outer tubularmember 232 opposite the end which the inner tubular member 234 protrudesfrom, the inner walls of the outer tubular member 232, and the sealedinterface between the piston attached to the inner tubular member 234and the inner diameter of the outer tubular member 232, according tosome embodiments. In some embodiments, as hydraulic fluid flows into thesecond chamber of double-action cylinder 230, hydraulic fluid leaves thefirst chamber of double-action cylinder 230, and the double-actioncylinder 230 expands. In some embodiments, as hydraulic fluid flows intothe first chamber of double-action cylinder 230, hydraulic fluid leavesthe second chamber of double-action cylinder 230, and the double-actioncylinder 230 retracts. The inlet/outlet port 260 may be the inlet/outletport for the first chamber, and the inlet/outlet port 262 may be theinlet/outlet port 262 for the second chamber, according to someembodiments.

In some embodiments, the front and rear double-action cylinders 230 maybe hydraulically linked, such that when hydraulic fluid leaves the firstchamber and enters the second chamber of the front double-actioncylinder 230 (i.e., the front double-action cylinder 230 expands),hydraulic fluid enters the first chamber and leaves the second chamberof the rear double-action cylinder 230 (i.e., the rear double-actioncylinder 230 retracts). In some embodiments, the front and reardouble-action cylinders 230 may be hydraulically linked, such that whenhydraulic fluid leaves the second chamber and enters the first chamberof the front double-action cylinder 230 (i.e., the front double-actioncylinder 230 retracts), hydraulic fluid enters the second chamber andleaves the first chamber of the rear double-action cylinder 230 (i.e.,the rear double-action cylinder expands). In some embodiments, the firstchamber of the front double-action cylinder 230 is hydraulically linkedto the second chamber of the rear double-action cylinder 230 and thesecond chamber of the front double-action cylinder 230 is hydraulicallylinked to the first chamber of the rear double-action cylinder 230.

As stated above, the flow of fluid between the first chamber of thefront double-action cylinder 230 and the second chamber of the reardouble-action cylinder 230, and the flow of fluid between the secondchamber of the front double-action cylinder 230 and the first chamber ofthe rear double-action cylinder 230 may be facilitated by theinlet/outlet ports 260 and 262 and hydraulic lines, according to someembodiments. For example, a first hydraulic line may be attached to theinlet/outlet port 260 of the front double-action cylinder 230 and theinlet/outlet port 262 of the rear double-action cylinder 230, while asecond hydraulic line may be attached to the inlet/outlet port 262 ofthe front double-action cylinder 230 and the inlet/outlet port 260 ofthe rear-double action cylinder 230, according to some embodiments. Thismay produce a closed fluid circuit between the inlet/outlet ports 260and 262 of the front and rear double-action cylinders 230, with thefront double-action cylinder 230 being driven (i.e., expanded orretracted) by the tongue 244 driven by the motion of the vehicle, andthe rear double-action cylinder 230 being driven (i.e., expanded orretracted) due to the hydraulic fluid transferred to or from the firstor second chambers of the front double-action hydraulic cylinder 230,according to some embodiments.

Tongue 244 may be produced from steel, and may be generallysquare-shaped in its cross section, according to some embodiments. Insome embodiments, the cross-sectional shape of tongue 244 may begenerally I-shaped, generally rectangular, etc., or any other shape.According to some embodiments, tongue 244 may include connecting portion246 integrally formed with tongue 244 near its end. Connecting portion246 may include a through-hole and may be configured to attach to a beamfor towing or transportation purposes in some embodiments. In someembodiments, the beam may connect to a trailer hitch on the vehicle, andthe other end of the beam may connect to the connecting portion 246 witha removable pin. The beam may act as a tensile load-carrying member,transferring a towing force from the vehicle to the tongue 244 to towthe agricultural machine according to some embodiments. In someembodiments, when the vehicle turns, the tongue 244 (in the front axleassembly 204) is caused to pivot by the turning motion of the vehicle,transferred through the beam. This may cause tongue 244 to drive theexpansion/retraction of the front double-action cylinder 230. In someembodiments, tongue 244 is connected to tongue halves 266. Tongue halves266 may be pinned to tongue 244 with removable pin 268. In someembodiments, tongue halves 266 are integrally formed with tongue 244.Tongue halves 266 may be positioned between centering bar 252 and tongue244 according to some embodiments. In some embodiments, centering bar252, tongue halves 266, and tongue 244 are all pinned with pin 268. Insome embodiments, tongue halves 266 are integrally formed with centeringbar 252. Tongue halves 266 may extend substantially the entire length oftongue 244 according to some embodiments. Tongue halves 266 may be madefrom steel and may have a generally square or generally rectangularcross-sectional shape. In some embodiments, tongue halves 266 areintegrally formed with tongue 244.

Tie rods 228 are configured to steer wheels 224 to determine a turndirection according to some embodiments. Therefore, the expansion andretraction of double-action cylinder 230 may determine the turndirection, according to some embodiments. In some embodiments, tie rods228 are generally circular in their cross-sectional shape. In someembodiments, the cross-sectional shape of tie rods 228 may be generallyoval, generally square, generally rectangular, or any other shape. Tierods 228 may be substantially the same length, according to someembodiments. Tie rods 228 may have eye portions near their endsconfigured to connect to the joint 258 on one end and to connect towheel hub 222 on the other end.

Referring still to FIGS. 3-4, axle assembly 204 is shown to includestruts 240. Struts 240 may be made of steel and may have cross-sectionalshape that is I-shaped according to some embodiments. In someembodiments, struts 240 may have a cross-sectional shape that isgenerally rectangular, generally circular, etc. According to someembodiments, struts 240 may have through-holes distributed along thelongitudinal length, which may decrease the weight and material of thestruts 240. In some embodiments, struts 240 are configured to connect onone end to strut mounts 242 and connect on their other end to header256. Struts 240 may be removable according to some embodiments. In someembodiments, struts 240 connect to strut mounts 242, which connects tostrut connector 264. Strut connector 264 connects the strut mounts 242to horizontal axle 226, according to some embodiments. According to someembodiments, the connection between the strut connector 264 and thehorizontal axle 226 is a fixed connection. Horizontal axle 226 may haveaxle reinforcement 270 which provides additional strength to horizontalaxle 226 according to some embodiments. In some embodiments, thehorizontal axle 226 may be generally circular.

In some embodiments, the double-action cylinder 230 of the two axleassemblies 204 are hydraulically connected. Since both axle assemblies204 have the same general configuration, both axle assemblies 204 areconfigured to turn wheels 224, resulting in a four-wheel steeringsystem. Double-action cylinders 230 are configured to hydraulicallyconnect to each other to produce a turning radius smaller than if onlyone of the wheel assemblies 208 were steerable. According to someembodiments, the expansion and retraction amounts of the double-actioncylinders 230 are equal. For example, when double-action cylinder 230shown in FIG. 3 expands 1 cm, the other double-action cylinder 230 maybe configured to expand 1 cm as well according to some embodiments. Insome embodiments, the expansion and retraction of the double-actioncylinders 230 are not equal. For example, when double-action cylinder230 shown in FIG. 3 expands 1 cm, the other double-action cylinder 230(not shown) may be configured to expand 0.5 cm according to someembodiments. According to some embodiments, the expansion and retractionof the double-action cylinders 230 are inversely proportional. Forexample, when double-action cylinder 230 shown in FIG. 3 expands 1 cm,the other double-action cylinder 230 may be configured to retract 1 cm(or 0.5 cm, or 1.5 cm, etc.) according to some embodiments. In someembodiments, the length of the tongue 244 is not equal between the twoaxle assemblies 204. Therefore, the same amount of expansion orretraction of the double-action cylinders 230 may not correspond toequal angular pivot displacements of the tongue 244 according to someembodiments. In some embodiments, the relationship between the angulardisplacement of the front wheels 224 and the rear wheels 224 due to theexpansion or retraction of double-action cylinder 230 is linear (e.g.,when the front wheels rotate 30 degrees, the rear wheels rotate 30degrees in a direction to produce the same turn as the front wheels). Insome embodiments, the relationship between the angular displacement ofthe front wheels 224 and the rear wheels 224 due to the expansion orretraction of the double-action cylinder 230 is inversely linear (e.g.,when the front wheels rotate 30 degrees, the rear wheels rotate −30degrees). In some embodiments, the relationship between the angulardisplacement of the front wheels 224 and the rear wheels 224 due to theexpansion or retraction of the double-action cylinder 230 may benon-linear (e.g., when the front wheels rotate 30 degrees, the rearwheels rotate 15 degrees, when the front wheels rotate 60 degrees, therear wheels rotate 30 degrees, when the front wheels rotate 70 degreesthe rear wheels rotate 35 degrees, etc.). Some or any of theserelationships between the rotation of the front wheels 224 and the rearwheels 224 due to the expansion and retraction of the double-actioncylinders 230, may be obtained by using different lengths of the tongue244, the outer tubular member 232, or the inner tubular member 234.

In some embodiments, the tongue 244 drives the double-action cylinder230. For example, if the tongue 244 is connected to a vehicle and thevehicle makes a turn, this will cause the tongue 244 to move and toactuate double-action cylinder 230. In some embodiments, thedouble-action cylinder 230 which is driven by the tongue 244 only occurson the front axle assembly 204. The rear axle assembly 204 may includedouble-action cylinder 230 that is hydraulically linked to the operationof the double-action cylinder 230 of the front axle assembly 204according to some embodiments. The tongue is configured to pivot due tothe direction of turn of the vehicle, and to expand or contract thefront double-action cylinder 230 based on the movement of the tongue244, according to some embodiments. In some embodiments, the tongue 244pivots in direction and magnitude proportional to the turn of thevehicle. For example, if the vehicle makes a sharp right turn, tongue244 may pivot +35 degrees, according to some embodiments. In someembodiments, if the vehicle makes a slight left turn, tongue 244 maypivot −15 degrees. In some embodiments, the direction and magnitude ofthe pivoting of the tongue 244, which is proportional to the magnitudeand direction of turn of the vehicle, may cause the front double-actioncylinder 230 to expand or retract (direction) a certain length(magnitude). According to some embodiments, the rear double-actioncylinder 230 is hydraulically linked to the front double-action cylinder230 and expands or retracts based on the operation of the frontdouble-action hydraulic cylinder 230 (i.e., the rear double-actioncylinder 230 expands or retracts due to the fluid transfer from thefront double-action cylinder 230). In this way, the direction andmagnitude of the turn of the vehicle is transferred to the frontdouble-action cylinder 230 through the tongue 244, and to the reardouble-action cylinder 230, resulting in four-wheel steering accordingto some embodiments. According to some embodiments, the relationshipbetween the operation of the front double-action cylinder 230 (as drivenby the tongue 244) and the rear double-action cylinder 230 is any of therelationships discussed above (e.g., linear, non-linear, based onexpansion or retraction length, based on turn angle of wheels, etc.).For example, in some embodiments, when the vehicle makes a sharp rightturn, the tongue 244 may pivot +35 degrees, causing the frontdouble-action cylinder 230 to expand a length of 3 cm, while the reardouble-action cylinder 230 may retract only 1.5 cm.

In some embodiments, the double-action cylinders 230 are hydraulicallyconnected in their operation to each other through a hydraulic fluidcircuit. In some embodiments, the relationship between the expansion andretraction of the front and rear double-action cylinders 230 may berelated to fluid quantity. For example, as 10 mL of hydraulic fluidleaves or enters the front double-action cylinder 230 as it retracts orexpands, 10 mL of hydraulic fluid may leave or enter the reardouble-action cylinder 230 causing it to expand or retract and viceversa. In some embodiments, the relationship between the fluid enteringor leaving the front double-action cylinder 230 and the fluid enteringor leaving the rear double-action cylinder 230 is non-linear. In someembodiments, a controller may be present in the hydraulic fluid circuit,configured to control the operation of a pump. The controller may beconfigured to control the pump to pump fluid between a fluid reservoirand the front and/or rear double-action cylinders 230. The controllermay pump fluid between the front and/or rear double-action cylinders 230based on the operation of the front or rear double-action cylinders 230which may be determined by the pivoting of the tongue 244 which isdirectly related to the magnitude and turn of the vehicle. In someembodiments, the controller may receive information from a wheel speedsensor or a magnitude of turn sensor and adjust the operation of thepump (or the relationship between the rotation of the front and rearwheels 224) based on information received from the wheel speed sensor orthe magnitude of turn sensor. For example, the controller may beconfigured to control the pump to expand or retract the reardouble-action cylinder 230 only during sharp turns when four-wheelsteering is necessary.

Due to the similar configurations of the front and rear wheel assemblies208, both wheel assemblies 208 can steer due to the double-actioncylinder 230, according to some embodiments. In some embodiments, thisresults in four-wheel steering. Four-wheel steering provides manyadvantages. For example, when the agricultural harvesting head 200 (orany other agricultural machine) is being transported behind a vehicle,the driver may need to make sharp turns in order to avoid obstacles inthe road or to even simply make a sharp turn around a corner.Agricultural machines that are being transported behind vehicles canoften be very long (typically much longer than the average length of atruck), and this can make transporting the agricultural machines verydifficult. If the vehicle operator cannot make a sharp turn on a route,it may limit the route that the operator can take, and this can addadditional cost and time to transporting the agricultural machine. Ifthe operator decides to take a route with a sharp turn or must make asharp turn to avoid something in the road, the rear wheels may skid if atwo-wheel steering system is used. The desired turn may be too sharp forthe two-wheel steering system, and this may cause the rear wheels todrag along the ground. This is undesirable since it may wear out thetires, and may introduce transverse loads into the axle which may damagethe axle, the wheel bearings, or any other part of the axle assembly. Insome embodiments, if the desired turn is too sharp for the two-wheelsteering system (e.g., a turn exceeds turning limits of the two-wheelsteering system), tongue 244 may receive an excessive bending force andif the bending force becomes too great, tongue 244 may bend (e.g.,deform). Wheel dragging/scrubbing may also occur during harvesting orwhile using the agricultural machine in field mode if the operator makesa turn which is too sharp. This can cause the same problems as when asharp turn is made on the road (transverse loads, wearing of tires,etc.), and additionally may produce ruts in the soil or forciblyintroduce dirt into the axle system. Using a four-wheel steering systemas described above may solve these problems. The four-wheel steeringsystem enables the vehicle driver to make sharp turns while duringtransportation, and also enables the agricultural machine operator tomake sharp turns when using the agricultural machine in a field.Additionally, the four-wheel steering may decrease the likelihood oftipping at high speeds. This may enable the vehicle operator to travelfaster during transportation without risk of rolling over and damagingthe agricultural machine. Advantageously, this may reduce in thetransportation time, enabling faster transportation.

Referring still to FIGS. 3-4, the axle assembly 204 is shown to includespring 248, which is connected on one end to spring mount 250, andconnected to centering bar 252 on the other end, according to someembodiments. In some embodiments, centering bar 252 is pinned to tongue244. Spring 248 may in some embodiments provide a centering force forthe rollover function while in field mode. In some embodiments, spring248 is configured to provide a force to the outside wheel 224 (the onlywheel shown in FIG. 3) during a turn. For example, when the spring 248is expanded due to the expansion of double-action cylinder 230, itproduces a tensile force between the centering bar 252 and the springmount 250. This force is transmitted through centering bar 252, tongue244, and the left tie rod 228 of FIG. 3 to the left (outside) wheel 224of FIG. 3 according to some embodiments.

In some embodiments, the front double-action cylinder 230 is connectedto the tongue 244 which pivots about pin joint 254. The tongue 244 maybe driven by the vehicle through the beam connected to connectingportion 246 according to some embodiments. As the vehicle makes a turn,the tongue 244 is caused to pivot, and the front double-action cylinder230 expands or retracts according to some embodiments. The tongue 244 isalso connected to the tie rods 228, and the pivoting of the tongue 244causes the tie rods 228 to move and steer the wheels 224, according tosome embodiments. As the front double-action cylinder 230 expands orretracts, hydraulic fluid enters or leaves the first or second chamberof the front double-action cylinder 230, through inlet/outlet ports 260and 262 according to some embodiments. Hydraulic fluid is transferred toor from the front double-action cylinder 230 and the rear-double actioncylinder 230 through hydraulic fluid lines connected to the inlet/outletports 260 and 262 of the front and rear double-action cylinders 230according to some embodiments. When hydraulic fluid is transferred toand from the front double-action cylinder 230 and the rear double-actioncylinder 230, rear double-action cylinder 230 expands or retracts due tothe transfer of hydraulic fluid into and out of the first and secondchambers (or the second and first chambers) of double-action cylinder230 respectively, according to some embodiments. The expansion orretraction of rear double-action cylinder 230 causes the tongue 244 ofthe rear wheel assembly 208 to pivot, according to some embodiments.When the tongue 244 of the rear wheel assembly 208 pivots due to theexpansion or retraction of rear double-action cylinder 230, the tongue244 of the rear wheel assembly 208 drives the tie rods 228 of the rearwheel assembly 208, according to some embodiments. The tie rods 228 ofthe rear wheel assembly 208 are connected to the wheels 224 of the rearwheel assembly 208, according to some embodiments. As the tie rods 228of the rear wheel assembly 208 are driven by the tongue 244 of the rearwheel assembly 208, the tie rods 228 of the rear wheel assembly 208steer the wheels 224 of the rear wheel assembly 208, according to someembodiments. Therefore, as the front wheel assembly 208 is steered tomake a turn, the rear wheel assembly 208 is also steered in a directionconducive to the turn of the vehicle, according to some embodiments.

Another advantage of the present invention is that both the wheelassemblies 208 may be symmetrical, according to some embodiments.Therefore, when parts are manufactured or must be replaced, the sameparts can be used for both wheel assemblies 208. Often times,agricultural machines that have wheels for transporting will usedifferent configurations for the front and rear wheel assemblies andunique parts must be manufactured for both of these wheel assemblies.The present invention presents a standardized wheel assembly 208 thatmay be used on the front and rear, and may reduce tipping and implementfour-wheel steering, according to some embodiments.

While this specification contains many specific implementation details,these should not be construed as limitations on the scope of what may beclaimed, but rather as descriptions of features specific to particularimplementations. Certain features described in this specification in thecontext of separate implementations can also be implemented incombination in a single implementation. Conversely, various featuresdescribed in the context of a single implementation can also beimplemented in multiple implementations separately or in any suitablesub combination. Moreover, although features may be described above asacting in certain combinations and even initially claimed as such, oneor more features from a claimed combination can in some cases be excisedfrom the combination, and the claimed combination may be directed to asubcombination or variation of a subcombination.

Although the present disclosure is illustrated by the example of aheader of a harvest machine, the present disclosure may be applied tovarious machines that are similar to the header of a harvest machinethat need to be transported between different field sites.

It should be understood that while the use of words such as desirable orsuitable utilized in the description above indicate that the feature sodescribed may be more desirable, it nonetheless may not be necessary andembodiments lacking the same may be contemplated as within the scope ofthe invention, the scope being defined by the claims that follow. Inreading the claims, it is intended that when words such as “a,” “an,” or“at least one” are used there is no intention to limit the claim to onlyone item unless specifically stated to the contrary in the claim.

It should be noted that certain passages of this disclosure canreference terms such as “first” and “second” in connection with side andend, etc., for purposes of identifying or differentiating one fromanother or from others. These terms are not intended to merely relateentities (e.g., a first side and a second side) temporally or accordingto a sequence, although in some cases, these entities can include such arelationship. Nor do these terms limit the number of possible entities(e.g., sides or ends) that can operate within a system or environment.

The terms “connected” and the like as used herein mean the joining oftwo components directly or indirectly to one another. Such joining maybe stationary (e.g., permanent) or moveable (e.g., removable orreleasable). Such joining may be achieved with the two components or thetwo components and any additional intermediate components beingintegrally formed as a single unitary body with one another or with thetwo components or the two components and any additional intermediatecomponents being attached to one another.

What is claimed is:
 1. A harvesting head assembly for an agriculturalmachine, the harvesting head assembly comprising: at least a first wheelassembly comprising a plurality of wheels and an axle assembly, whereinthe plurality of wheels are rotatably coupled to the axle assembly, theplurality of wheels including at least a first wheel and a second wheelspaced from one another along the axle assembly such that the at leastfirst wheel assembly is configured to rotate between a field mode and atransportation mode relative to a header of the harvesting headassembly; a tongue and at least one tie rod of the axle assembly, wherethe tongue is pivotally coupled to the at least one tie rod; adouble-action cylinder connected at one end to the axle assembly and atan opposite end to the tongue, the double-action cylinder configured toexpand or retract such that the expanding and retracting of thedouble-action cylinder pivots the plurality of wheels as part of asteering function; and a spring coupled at one end to the axle assemblyand at another end to the tongue; wherein, the tongue is configured topivot as the double-action cylinder expands or retracts to pivot theplurality of wheels during the steering function; wherein, the at leastone tie rod is coupled between the tongue and a wheel hub of one of theplurality of wheels, the at least one tie rod configured to steer thewheels based on a pivotal movement of the tongue; wherein, the spring isconfigured to provide a centering force to at least one of the pluralityof wheels to reduce scrubbing of the at least one of the plurality ofwheels.
 2. The harvesting head assembly of claim 1, wherein the tongueis pivotally coupled to the axle assembly at a pivot joint.
 3. Theharvesting head assembly of claim 1, wherein the tongue comprises aconnecting portion integrally formed therewith, the connection portionincluding a defined through-hole for receiving a tensile load-carryingmember.
 4. The harvesting head assembly of claim 1, wherein the tongueis operably coupled to tongue halves via a removable pin.
 5. Theharvesting head assembly of claim 4, further comprising a centering barcoupled to the tongue and tongue halves via the removable pin.
 6. Theharvesting head assembly of claim 1, further comprising at least onestrut coupled to the axle assembly via a strut mount and strutconnector.
 7. The harvesting head assembly of claim 1, furthercomprising a second wheel assembly, the second wheel assembly comprisinga plurality of wheels, an axle assembly, a tongue, a double-actioncylinder, and at least one tie rod; wherein, the tongue of the firstwheel assembly is configured to be driven to pivot about a pivot point,operably induce expansion and retraction of the double-action cylinder,and drive the at least one tie rod to steer the plurality of wheels ofthe first wheel assembly, and the tongue of the second wheel assembly isconfigured to be driven by the expansion and retraction of thedouble-action cylinder of the second wheel assembly, the tongue of thesecond wheel assembly driving the at least one tie rod to steer theplurality of wheels of the second wheel assembly based on the expansionand retraction of the double-action cylinder.
 8. The harvesting headassembly of claim 7, wherein the double-action cylinder of the first andsecond wheel assemblies each comprises a fluid inlet and a fluid outlet;wherein, the double-action cylinder of the first wheel assembly ishydraulically linked to the double-action cylinder of the second wheelassembly.
 9. The harvesting head assembly of claim 8, wherein anexpansion or retraction of the double-action cylinder of the first wheelassembly operably induces an expansion or retraction of thedouble-action cylinder of the second wheel assembly.
 10. The harvestinghead assembly of claim 8, wherein the hydraulic linkage between thedouble-action cylinders of the first and second wheel assemblies forms aclosed fluid circuit.
 11. The harvesting head assembly of claim 8,wherein: a first hydraulic line is fluidly coupled between an inlet ofthe double-action cylinder of the first wheel assembly and an outlet ofthe double-action cylinder of the second wheel assembly; a secondhydraulic line is fluidly coupled between an outlet of the double-actioncylinder of the first wheel assembly and an inlet of the double-actioncylinder of the second wheel assembly.
 12. The harvesting head assemblyof claim 8, wherein: the tongue of the first wheel assembly isconfigured to be operably pivoted via a steering movement of a towingvehicle; the double-action cylinder of the first wheel assembly isoperably expanded or retracted as a function of the pivotal movement ofthe tongue of the first wheel assembly; based on the expansion orretraction of the double-action cylinder of the first wheel assembly andthe hydraulic linkage between the double-action cylinder of the firstand second wheel assemblies, the double-action cylinder of the secondwheel assembly expands or retracts; the tongue of the second wheelassembly is pivoted based on the expansion or retraction of thedouble-action cylinder of the second wheel assembly.
 13. The harvestinghead assembly of claim 8, wherein the double-action cylinder of thefirst double-action cylinder is configured to transfer hydraulic fluidto the double-action cylinder of the second wheel assembly to expand orretract the double-action cylinder of the second wheel assembly.
 14. Theharvesting head assembly of claim 7, wherein the first and second wheelassemblies are symmetrically constructed.
 15. The harvesting headassembly of claim 1, wherein the spring connects at one end to acentering bar that is removably pinned with the tongue.
 16. Theharvesting head assembly of claim 1, wherein the plurality of wheels arespaced a distance apart greater than or equal to a width of theagricultural machine.
 17. A harvesting head assembly for an agriculturalmachine, the harvesting head assembly comprising: a wheel assemblyincluding a plurality of wheels and an axle assembly including an axle,wherein the plurality of wheels are rotatably coupled to the axle and isconfigured to rotate between a field mode and a transportation moderelative to a header of the harvesting head assembly; the axle assemblycomprising a tongue, one or more tie rods, a header, a double-actioncylinder, one or more struts, a centering bar, a spring, and a springmount; wherein: the tongue is pivotally coupled to the one or more tierods; the double-action cylinder connected at one end to the axleassembly and at an opposite end to the tongue, the double-actioncylinder configured to expand or retract such that the expanding andretracting of the double-action cylinder pivots the plurality of wheelsas part of a steering function; the spring coupled at one end to thespring mount and at another end to the centering bar; the tongue ispivotally moved as the double-action cylinder expands or retracts duringthe steering function; the spring is configured to provide a centeringforce to at least one of the plurality of wheels to reduce scrubbing ofthe at least one of the plurality of wheels.
 18. The harvesting headassembly of claim 17, wherein the one or more tie rods are coupledbetween the tongue and one of the plurality of wheels, the one or moretie rods being configured to pivot the one wheel of the plurality ofwheels based on a pivotal movement of the tongue.
 19. The harvestinghead assembly of claim 17, wherein: the centering bar is coupled to thetongue via a removable pin; an expansion of the double-action cylinderinduces an extension of the spring, and the extension of the springproduces a tensile force which is transferred through the centering bar,the tongue, and the one or more tie rods.
 20. The harvesting headassembly of claim 17, further comprising a second wheel assembly, thesecond wheel assembly comprising a second plurality of wheels and asecond axle assembly, wherein, the second axle assembly comprises atongue, one or more tie rods, a header, a double-action cylinder, one ormore struts, a centering bar, a spring, and a spring mount; wherein, thedouble-action cylinder of the first wheel assembly is hydraulicallycoupled to the double-action cylinder of the second wheel assembly;wherein, the tongue of the first wheel assembly is configured to bedriven to pivot about a pivot point, operably induce expansion andretraction of the double-action cylinder of the first wheel assembly,and drive the one or more tie rods to steer the plurality of wheels ofthe first wheel assembly; wherein, the tongue of the second wheelassembly is configured to be driven by the expansion and retraction ofthe double-action cylinder of the second wheel assembly; wherein, thetongue of the second wheel assembly operably drives the one or more tierods to steer the plurality of wheels of the second wheel assembly basedon the expansion and retraction of the double-action cylinder of thesecond wheel assembly.